1. Field of the Invention
The present invention relates to a crystal oscillator for surface mount, and more particularly, it relates to a surface mount crystal oscillator which can improve productivity and realize miniaturization and a manufacturing method of the same.
2. Description of the Related Art
[Prior Art]
A surface mount crystal oscillator is small-sized and lightweight, and is hence incorporated as a frequency or time reference source in a portable type electronic device.
In a conventional surface mount crystal oscillator, a crystal piece 2 is mounted on a ceramic substrate, and is covered and sealed with an inverted cover having a recessed shape. In recent years, there has been suggested an inexpensive household oscillator having a frequency deviation Δf/f which is comparatively loosely regulated, for example, from ±150 to ±250 ppm.
[Related Art]
It is to be noted that examples of a related art include Japanese Patent Application Laid-Open No. 2007-158419 ‘Surface Mount Crystal Oscillator’ (Nihon Dempa Kogyo Co., Ltd.) [Patent Document 1], Japanese Patent Application Laid-Open No. 2003-179456 ‘Surface Mount Container for Crystal Product and Crystal Product using the Same’ (Nihon Dempa Kogyo Co., Ltd.) [Patent Document 2], and Japanese Patent Application Laid-Open No. 2001-110925 ‘Conductive Cap, Electronic Component, and Method of forming Insulating Film on Conductive Cap’ (Murata Mfg. Co., Ltd.) [Patent Document 3].
Patent Document 1 discloses a constitution of a surface mount crystal oscillator in which a crystal piece 3 is mounted on an IC chip 2, the IC chip 2 and the like are formed on a mount substrate 4, and a metal cover 5 is disposed.
Moreover, Patent Document 2 discloses a constitution of a surface mount container for a crystal product in which a crystal piece 3 is disposed on a single layer substrate 1A via a crystal terminal 6, and is sealed with a cover 2.
Furthermore, Patent Document 3 discloses a constitution in which a contact face between a substrate 2 and a metal cap 3 to cover a piezoelectric element 4 formed on the substrate 2 has a curved inner side face.